Genetics II (Bio-205) Level 2 Lecture 5: Chromosome Painting

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What is a characteristic feature of B chromosomes in mammals?

They only appear in roots and not in aerial tissues.

They are smaller than A chromosomes.

They pair and recombine with A chromosomes during meiosis.

They have a distinct morphology from A chromosomes. (correct)

How do Bs in plants differ in size compared to A chromosomes?

Bs in plants are always larger than A chromosomes.

Bs in plants are always the same size as the largest A chromosome.

Bs in plants are the same size as A chromosomes.

Bs in plants are often smaller than the smallest A chromosome. (correct)

In mammals, where are B chromosomes often found?

Exclusively in aerial tissues

In pairs that recombine during meiosis

In varying numbers depending on the tissue type (correct)

Only in roots

Which process leads to non-Mendelian inheritance of B chromosomes in plants?

Post-meiotic non-disjunction Signup and view all the answers

What distinguishes Bs from As in terms of pairing and recombination during meiosis?

Bs pair and recombine with As during meiosis. Signup and view all the answers

Which statement accurately describes Bs in plant species like Zea mays?

Bs have a similar size to A chromosomes. Signup and view all the answers

What is the primary purpose of fluorescence in situ hybridization (FISH) in chromosome painting?

To identify specific regions or chromosomes within a cell's nucleus Signup and view all the answers

How have probe preparation and labeling techniques for FISH been modified over time?

Nucleotides can now be directly labeled with fluorescent dyes and incorporated into FISH probes Signup and view all the answers

What is the defining characteristic of B chromosomes?

They are extra chromosomes in addition to the standard chromosome complement Signup and view all the answers

How do B chromosomes typically maintain their presence in a population?

By displaying non-Mendelian inheritance via mitotic or meiotic drive mechanisms Signup and view all the answers

What is the primary source of B chromosomes in organisms?

They are derived from both autosomes and sex chromosomes in intra- and interspecies crosses Signup and view all the answers

What is the typical effect of high copy numbers of B chromosomes on the host genome?

They are deleterious to the host genome Signup and view all the answers

How do B-A translocations arise?

Through reciprocal translocations between Bs and As Signup and view all the answers

What is the purpose of using B-A translocations in maize genetics research?

To identify the location of recessive mutant genes on specific chromosome arms Signup and view all the answers

Why are truncated B chromosomes more readily recovered than truncated A chromosomes?

Bs are more dispensable than As Signup and view all the answers

What is the purpose of using telomere repeats in the construction of engineered mini-chromosomes?

To cleave the chromosome at the insertion point of the construct Signup and view all the answers

What is the main advantage of using engineered mini-chromosomes as platforms for stacking transgenes?

They allow for the integration of multiple transgenes at a single locus Signup and view all the answers

What is the key difference between B-A translocations and artificial chromosomes?

B-A translocations are naturally occurring, while artificial chromosomes are synthetic Signup and view all the answers

What is the primary purpose of chromosome painting?

To visualize specific chromosome regions or entire chromosomes Signup and view all the answers

Which technique involves the use of chromosome-specific DNA probes with multiple fluorochromes?

Fluorescence in situ hybridization (FISH) Signup and view all the answers

Which of the following statements about chromosome painting is NOT true?

It was initially used only for the study of animal chromosomes Signup and view all the answers

What is the significance of the translocation t(9;22)(q34;p11) mentioned in the text?

It led to the discovery of the Philadelphia chromosome Signup and view all the answers

In which field has chromosome painting been widely used?

All of the above Signup and view all the answers

What is the purpose of using human genomic DNA as a competitor in chromosome painting?

To improve the specificity of the chromosome-specific probes Signup and view all the answers

What is the key difference between the chromosomes of eukaryotes and prokaryotes?

Eukaryotic chromosomes are much longer and more complex than prokaryotic chromosomes. Signup and view all the answers

What is the purpose of the 'multineme and unineme' theories mentioned in the text?

To explain how the DNA in eukaryotic chromosomes is packaged during cell division. Signup and view all the answers

What is the approximate range of DNA content per human chromosome?

50-250 million nucleotide pairs Signup and view all the answers

What is the key difference between the chromosomes of eukaryotes and prokaryotes in terms of DNA content?

Eukaryotic chromosomes have orders of magnitude more DNA than prokaryotic chromosomes. Signup and view all the answers

What is the purpose of the statement that 'RNase treatment however will not affect the supercoiling of the domains of the chromosomes'?

To indicate that the supercoiling of eukaryotic chromosomes is not dependent on RNA. Signup and view all the answers

What is the key difference between the amount of DNA in a human diploid cell compared to a single E. coli cell?

A human diploid cell has about 1000 mm of DNA, while an E. coli cell has 1.5 mm of DNA. Signup and view all the answers